Background of 0.

Due to my work, I have many opportunities to contact Pie-Engine. When using pie-Engine these days, I found the data of Global Land 30 in it.

With this data, you can export the cropped data directly using pie-Engine.

1. Preparation of the study area

I uploaded the administrative data of Lezhi County, Ziyang City, Sichuan Province.After the data is uploaded, unlike GEE, the study area cannot be directly called and needs to be transformed into the geometry type.

// LZ (Ziyang City, Sichuan Province, Lezhi County)
LZ= LZ.first().geometry(); 
Map.centerObject(LZ,9);    
Map.addLayer(LZ, {color: 'FF0000'.fillColor: '00000000'.width: 1}, "LZ")
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2. Data filtering

Taking GLC data of 2020 as an example, we firstly load image set, screen time, select band, Mosaic and clipping.

GLC30 download of land use data in 2020
// Load land use data
var LZ_landcover_2020=pie.ImageCollection("NGCC/GLOBELAND30")
              .filterBounds(LZ)
              .filterDate("2020-1-01"."2020-12-31")
              .select(["B1"])
              .mosaic()
              .clip(LZ) ;
// Display land use data
Map.addLayer(LZ_landcover_2020,visParam,"LZ_landcover_2020")
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There are two things to note here:

PPQQ is PIE, which is different from GEE in that it needs to specify the band before cutting.

The second part of PPQQ is that the GLC data is not spliced, and the Mosaic function is needed to Mosaic the multi-scene data covering the research area.

3. Export data

This is almost the same as GEE, selecting the download area, download path, and so on.

/ / download
Export.image({
    image:LZ_landcover_2020,
    description: "LZ_landcover_2020".assetId: "LZ_landcover_2020".region:LZ,
    scale:30.maxPixels:1e13
});
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There are two things to note:

PPQQ If you don’t know the download area size, please remember to set the maxPixels larger;

PPQQ PIE data processing, in THE PIE resources, click the file can be downloaded;

4. Data use

After downloading the data and loading it into gis software, you can see the land use data of 30 meters in the study area in 2000, 2010 and 2020.

5. Code links

The code link feature provides two ways. One is external links for non-logged-in users: engine.piesat.cn/engine-shar… Is a kind of internal links, directly in the editor to open for login user directly use: engine. Piesat. Cn/engine/home…

6. Complete code

The data download code for 2020 is shown above, and copied for 2000 and 2010. Question: Why not loop? Because I’m lazy, I can’t loop as fast as CTRL +V.

var LZ = pie.FeatureCollection('user/15884411724/quhua/lezhixian')
// The research area is located in Ziyang City, Sichuan Province
LZ= LZ.first().geometry(); 
Map.centerObject(LZ,9);    
Map.addLayer(LZ, {color: 'FF0000'.fillColor: '00000000'.width: 1}, "LZ")

// Land use data style
var visParam = {
    min: 10.max: 100.palette: '#43B87C,#24DB99,#7EB451,#2E79BC,#2838B8,#8B2CC0,#EEE912,#BC1FA1,#17214F,#B81A74,#B5CF52,#932626,#2B328B,#AA5C5C,#2561E9 ,#874949,#4ECF61,#AE5151'
};

GLC30 Download land use data in 2000
// Load land use data filter, Mosaic, crop
var LZ_landcover_2000=pie.ImageCollection("NGCC/GLOBELAND30")
              .filterBounds(LZ)
              .filterDate("2000-1-01"."2000-12-31")
              .select(["B1"])
              .mosaic()
              .clip(LZ);
// Display land use data
Map.addLayer(LZ_landcover_2000,visParam,"LZ_landcover_2000")

/ / download
Export.image({
    image:LZ_landcover_2000,
    description: "LZ_landcover_2000".assetId: "LZ_landcover_2000".region:LZ,
    scale:30.maxPixels:1e13
});

GLC30 Download of land use data in 2010
// Load land use data
var LZ_landcover_2010=pie.ImageCollection("NGCC/GLOBELAND30")
              .filterBounds(LZ)
              .filterDate("2010-1-01"."2010-12-31")
              .select(["B1"])
              .mosaic()
              .clip(LZ) ;
// Display land use data
Map.addLayer(LZ_landcover_2010,visParam,"LZ_landcover_2010")

/ / download
Export.image({
    image:LZ_landcover_2010,
    description: "LZ_landcover_2010".assetId: "LZ_landcover_2010".region:LZ,
    scale:30.maxPixels:1e13
});

GLC30 download of land use data in 2020
// Load land use data
var LZ_landcover_2020=pie.ImageCollection("NGCC/GLOBELAND30")
              .filterBounds(LZ)
              .filterDate("2020-1-01"."2020-12-31")
              .select(["B1"])
              .mosaic()
              .clip(LZ) ;
// Display land use data
Map.addLayer(LZ_landcover_2020,visParam,"LZ_landcover_2020")

/ / download
Export.image({
    image:LZ_landcover_2020,
    description: "LZ_landcover_2020".assetId: "LZ_landcover_2020".region:LZ,
    scale:30.maxPixels:1e13
});

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